The present invention relates to a device Pilot Control Unit, Valve Arrangement, and Method for the Regulated Provision of a Fluid
The present disclosure relates to a pilot control unit for providing a pilot control pressure for a valve unit for a regulated provision of a fluid, wherein the pilot control unit comprises at least one pilot control valve, in particular at least one electrically controlled pilot control valve, and a regulating unit which is coupled to the pilot control unit. The disclosure further relates to a valve arrangement having a pilot control unit of this type. Finally, the disclosure relates to a method for the adaptive, parameter-based regulation of a pilot control pressure for a valve unit for the regulated provision of a fluid and to a corresponding machine control program for carrying out the method.
US 2015/0268669 A1 discloses a device for providing a fluid having a regulated outlet pressure. The known device is provided with a pressure control unit that is controlled via a pilot control pressure and at which an inlet for the fluid, an outlet for the fluid and a first valve unit acting between the inlet and the outlet is provided. The device also is provided with a pilot control unit that provides the pilot control pressure. The pressure control unit comprises a first diaphragm, on which the pilot control pressure acts, and a second diaphragm, which is mechanically coupled to the first diaphragm and on which the fluid having the outlet pressure acts, wherein at least the second membrane mechanically acts on the first valve unit. The pilot control unit comprises, for example, two electrically controlled proportional valves for generating the pilot control pressure, wherein a first proportional valve is provided for increasing the pilot control pressure and a second proportional valve is provided for reducing the pilot control pressure.
The known device already provides for highly precise pressure regulation having accuracies in the range of better than 1%, preferably better than 0.5%. A further advantage of the known device is the low-power pressure regulation, since only a small amount of electrical power is required for operating the pilot control unit. The power requirement and the control performance benefit from the pilot control unit which is designed for controlling the main valve. The pilot control unit also can be referred to as a pilot unit. Valves of the pilot control unit also can be referred to as pilot valves.
A further advantage of the device known from US 2015/0268669 A1 derives from the low-friction mounting of movable parts of the main valve of the device, which also can improve the control performance. Static friction, stick-slip effects and the like can be largely avoided. It is further advantageous that outlet pressures which are provided can assume values that almost reach a level of the inlet pressures. This is because very little energy is required for the pressure control.
It has been shown, however, that there is a need to further increase the accuracy. There is a need for valve arrangements that have a highly stable operating behavior, wherein the accuracy can be influenced by drift or the like preferably only to a low extent or even a negligible extent.